| Author |
Message |
    
Pamela O. Brown (Pammy)
| | Posted on Sunday, November 05, 2000 - 12:56 pm: | 
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I do agree with Aaron about the exhaust augmented intake flow......
I think Ron will back me up on this further point(jump in anytime, Ron)
Friction, pressure and inertial forces are present as the mixture flows through the system of intake pipes, ports, chambers and valves. The relative importance of each component on the gas velocity and the size and shape of the ports. Although valve design, port design and manifold design are interrelated, several seperate processes can be determined seperately that will have an influence on volumetric efficiency.
During the intake event, due to the flow restrictions of the individual components, cylinder pressure is less than atmospheric. This pressure drop is the sum of the pressure loss at each component in the intake system: carburetor, and throttle, manifold, inlet port, inlet valve and air filter and box. Each loss is a small percentage with the port and valve curtain area being the largest. Consequently, the pressure in the cylinder during the intake process when the piston is at its highest velocity is only 10-15 percent below atmospheric pressure.
Right Ron? |
Steve Madden (Smadd)
| | Posted on Sunday, November 05, 2000 - 01:16 pm: |
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You know guys... there really isn't a Wes. It's Pammy in disguise because real men would never buy hop-up work from a blonde woman!! LOL
Sorry Pammy
Hope you enjoyed your ride this morning. *Wish* I could've joined you!! |
Aaron Wilson (Aaron)
| | Posted on Sunday, November 05, 2000 - 02:00 pm: |
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Rocket: let it go, man! Nobody wants to quibble over what Frank said or whether your constant is better than what Denish recommends.
FWIW, I honestly don't know how to doctor a dyno's results upward. I can sure as hell doctor'em downward, though. But when I'm dyno tuning, I'm putting all my effort into getting a repeatable result. That's what you have to do when you make a change and you're looking for something that may make only a small percentage difference.
The thing I have the hardest time controlling is the engine's temp. Screw that up and you'll get a bogus result. Downward.
Pammy: great post.
See ya,
AW |
Sean Pepper (Rocketman)
| | Posted on Sunday, November 05, 2000 - 02:44 pm: |
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OK, I let it go, but I think we are onto a good tech topic here, which is a direct result of our little disagreement, and I think we should continue it some more, in the quest of more knowledge, as per usuall !
Tell me this though, and in absence of your RR's "sheet", you explained how getting low lift cylinder fill was worth a bunch of power, how come it isn't there until 5 grand ? After all, your comment makes me think you have a high amount of torque at the bottom end and I'd assume higher still at the top end !
Go on man, post the damn chart, after all, anyone can read it, but trying to replicate it is another thing altogether !
I also thinks you too modest my friend. How can you say the race bike has a reasonable amount of power ? Didn't you guys ring its neck for all its worth ?
And please understand, this post is not meant in any way to be provocative 
Rocket in England |
OLD WIERD BOB (Stoneagedude)
| | Posted on Sunday, November 05, 2000 - 03:13 pm: |
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After monitoring you guys/gals for some time, the time has come to speak. Your vicious attack on Rocket in England has me all bent out of shape. Hey, he's DA MAN. He has pointed out the error of your ways many times. He knows how to ride backwards at a high rate of those kilometer things. (I can do that only at slow speeds) He knows how to make the frame look bitchen (I use a rattle can) He knows how to burn up a rear tire (I get 4 K from mine) And there is no doubt in my mind he knows DYNOS (I only know about dinos) I have great respect for this man - except for the thing about fat chicks...He will never know the joys of playing "boodle" - Ya gotta put up with a little blubber if ya wanta play boodle. Hey Rocket, I'll defend ya. I just may come out of the gorge and snapp off a few heads for ya. Whata you guys think of that...Huh? Huh? Hey, and I love that space alien skid lid...I want one!!! I now return to lurking in the ferns.......... |
Ron Dickey (Axtell)
| | Posted on Sunday, November 05, 2000 - 04:40 pm: |
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Aaron--I wasn't throwing out bait. I was just making a statement. You are dead right in everything you said. The battle cry should be "give me more torque at all rpms"
Pammy---you are also right. Isnt it a bear to start typing engine logic and realize that it will take a book the size of "War and Peace"
to explain everything and wherever you stop typing it still can be taken out of context?
Good Job! |
Aaron Wilson (Aaron)
| | Posted on Sunday, November 05, 2000 - 06:59 pm: |
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Ron: I know you weren't baiting, I was just teasing a little. And I'd buy that book. Start typing.
Rocket: I was referring to the overlap event. Not much lift at that point, yet it's very important for good cylinder fill.
On the race bike, we ran as much overlap as we could fit, and then made an exhaust system that hit the overlap with a strong negative wave at a good high rpm. Hence it gets more cylinder fill than it otherwise would, holds the torque up, and that makes power.
Problem is, that same setup gives little or no wave at lesser rpms. So the valves are hanging open, nobody's sucking out the exhaust (in fact there's a whole bunch of hot spent gas in there), and the piston starts down. Guess what happens?
Do you have Volume 2 of Denish's book? Great book, he has a layman's explanation of engine theory. See where he talks about rwhp per in3? For a Sporty or 4 cam BT:
mild: below 1.10
moderate: 1.10 to 1.25
race: 1.25 to 1.45
max effort: 1.45 to 1.75
I think this table is pretty accurate.
Ron has an 88" Sportster that makes 154rwhp (1.75, actually better because a 3.8125 square motor is really only 87.05", why do people call'em 88" anyway?). That's pretty much state of the art. Dual carb, which is what you'll find at the top end of the scale.
By comparison, The XR750 can break 2. But it's a little easier for a small engine. Still, it shows you how well that motor runs.
Chevy small blocks can also break 2.
The XR1000 can't come close, or at least I don't know how to make it come close. It's basically a long stroke XR750, which means you're trying to feed 33% more displacement with the same heads. Doesn't take a "Rocket" scientist to figure out where that constraint is. It's really not an ideal motor at all. It's myth is a whole bunch bigger than it's reality.
See ya,
AW |
Dave Tripp (Tripper)
| | Posted on Sunday, November 05, 2000 - 08:42 pm: |
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Where has this StoneAgeDude been hiding? Check out this profile. (one of my simple entertainment pastimes) |
Sean Pepper (Rocketman)
| | Posted on Sunday, November 05, 2000 - 10:06 pm: |
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Aaron: nope I don't and I need to get it, so I'll do that right now ! Thanks for reminding me.
What happens next is the piston starts down and you have very little pressure (below atmospheric) in the inlet manifold, due to small throttle opening, and with both valves open the pressure in the cylinder doesn't drop appreciably so you end up with a rush of exhaust gas entering the inlet manifold which of course means those spent gases are gonna come around again on the next induction stroke. Doesn't make for a very streetable motor, non or lumpy tickover, but providing you are not needing maximum power here, it works well in a race bike, in particular, a LSR bike. How did I do ?
XR 1000's, as Sporties go, the XR is King. That is the best looking Sportster ever built. Mean as a snake ! Just love 'em ! Still, my S1W has stolen my heart, and it is a well known fact, you can't ride two bikes with one arse !
Trippy Dave, I'm still rolling on the floor ! Come on, who the hells taking the pi$$. Stone Age Dude indeed ! Tell ya what though, if he's for real, he needs to post more often. Since the board has a new set of rules and a deputy, it's a refreshing change to find a loose tongued loony joining us, even if he is a fan of mine !
Stone Age Dude, please come back !
Rocket in England, in need of more fans.
ps, Pammy, never one to conform, HAPPY BELATED BIRFDAY BABE ! Better to be late than follow everyone else, like sheep. What did you get, besides the obvious and a hangover ? |
Pamela O. Brown (Pammy)
| | Posted on Monday, November 06, 2000 - 08:23 am: |
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I got to get out by myself and take a long ride with my new IDS (compliments of Supertrapp). I was present with a new mini disc player when I got back home (someone stole my old one). I have been missing it severly. All in all, it was a great birthday.
You are right Ron...I know I ended that little dissertation in an inappropriate spot...but I am not really adept at typing....I could have gone on all day.(really bored myself to tears)
Pammy |
John Sachs (Johnsachs)
| | Posted on Monday, November 06, 2000 - 05:31 pm: |
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Rocket,
I know that is a pretty poor/blur dyno sheet,but it's 119.6 lbs.ft. and 139h.p.Also,like Wes' bike,Jim's bike won A.M.I. h.p. shootout with 133.7 @ 14lbs. boost on their Superflow dyno(usually shows approx. 5% less than Dynojet). |
Sean Pepper (Rocketman)
| | Posted on Monday, November 06, 2000 - 07:45 pm: |
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John, excuse my mistake. I read, what bit I could, completely wrong.
Did Wes and Jim, kick the drum like Aaron does ?
Rocket in England |
Sean Pepper (Rocketman)
| | Posted on Monday, November 06, 2000 - 07:56 pm: |
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So Pammy, your ears will once again be filled with Elton John and Don Henley CD's ?
As Elton goes, the best album's he ever did was Elton John, around about 69 or 70 I recall, and Tumbleweed Connection. Of course, he was raw t
Rocket in England |
John Sachs (Johnsachs)
| | Posted on Monday, November 06, 2000 - 08:08 pm: |
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Rocket,
Superflow's kick back!
John |
Pamela O. Brown (Pammy)
| | Posted on Monday, November 06, 2000 - 10:10 pm: |
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I love Elton and Don....
Elton's home video, Tiara's and Tantrums or whatever it was called....showed him to be the ultimate brat...
Rocket, have you ever heard of a guy named Steve Burns, from Manchester? I know him well....
Pammy |
Sean Pepper (Rocketman)
| | Posted on Monday, November 06, 2000 - 10:50 pm: |
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Pammy, either you've asked me before , or I recognise his name !
Who is he ?
Is he a drag racer or a backing vocalist for queen Elton ?
Rocket in England |
Pamela O. Brown (Pammy)
| | Posted on Tuesday, November 07, 2000 - 08:19 am: |
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Drag racer, used-to-be. Was in the guinness book of world records for awhile for a 152+ mile per hour wheelie through the quarter mile. He has been in the Bike publications (Performance bikes?) many times. You were saying what a small place your country is...I just figured you would have heard of him, since the interests are similar.
He was paralized(again) doing an exhibition run in czechoslovacia(sp?) quite a few years back.
He can still walk...but not without crutches now.
Pammy |
'00 M2 (Blake)
| | Posted on Wednesday, November 08, 2000 - 11:50 pm: |
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Page topic? Ahem...
D Y N O Charts!!!
Could y'all do me a favor and stay on topic here a little bit?
Later,
Blake (anal BadWeB admin) |
Greg Gower (Leveg)
| | Posted on Sunday, November 12, 2000 - 02:33 am: |
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Just a comment on flow figures, and horsepower calculations from same - the constant most commonly used is originally from Superflow, and is pretty old now. A good race engine on race gas or alcohol can generally exceed this figure by around 10%, a Pro Stock type engine will exceed it by more than 20%.
However - the horsepower figure derived from this calculation is only potential horsepower. To attain it with a streetable engine requires that everything else needed to make that horsepower is available including appropriate compression, cam, exhaust, intake system, etc.
Greg |
Pamela O. Brown (Pammy)
| | Posted on Sunday, November 12, 2000 - 08:39 am: |
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Right on Greg!
Everything is relative...Good heads and garbage everything else = low hp. Garbage heads and good everything else = low hp. As a matter of fact just have one bad apple(part) can spoil the whole bunch.
Pammy....maybe I'll bake a pie |
Sean Pepper (Rocketman)
| | Posted on Sunday, November 12, 2000 - 08:56 am: |
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So Greg, a constant of .43, as Denish suggest for an optimum tuned motor, will now be .473 ?
Does this mean my own guesstimated constant of .35 may have to be raised, because the constant you suggest is for an even higher tuned motor, or are we just raising the envelope and what has gone before stays the same except the "distance" betwixt the constants has just widened ?
ie: .25 to .473 ?
Rocket in England, bench racing |
'00 M2 (Blake)
| | Posted on Sunday, November 12, 2000 - 02:06 pm: |
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err.. dyno charts? |
Sean Pepper (Rocketman)
| | Posted on Sunday, November 12, 2000 - 03:37 pm: |
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Blake: I understand your wanting for this page to be dyno charts only, but in my opinion, I think you may have created a good chat page anyway, dyno charts and all !
After all, dyno charts have a topic all of their own as some of the previous post's here have shown. Perhaps we should rename the page Dyno Charts and Race Math ?
Rocket in England |
DUNCAN PEACE (Peace)
| | Posted on Monday, November 13, 2000 - 04:53 pm: |
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Rocket,
I can't believe the arguments you're having about who`s got what hp.There are, in my eyes, too many variables in comparisons of dyno graphs, to possibly say as to who has the right amount of power for their spec of motor.I understand the relevance of the maths used to get an idea of what kind of power yours and everyone else`s spec of bike should put out,but at the end of the day comparison`s of bikes power output is relevant only if the bikes are dynoed the same day and roughly the same time.
Rocket,i built your engine and many like it,and before i build anyhing with my hands it is always done first using programs such as accelorator pro 3.Even programs like this cannot give you the exact power of your bike,but they can get you in the ballpark.The X1 we raced this year has given us slightly different readings using different dyno's,our dynojet 200 gave us readings of around the 127rwhp,yet when dynoed a week later on a dyno 150,it gave 129rwhp in the morning and 124rwhp in the afternoon.Make that as you will.Anyway enjoy your bike and we will get it in the 10's next year.
Peaceman. |
Sean Pepper (Rocketman)
| | Posted on Monday, November 13, 2000 - 07:41 pm: |
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Peaceman : you don't have to explain it to me, I understand it perfectly. It is when other folks question what I might have, that I sometimes find the need to explain things the way I see them.
I do this based on exactly the reasons you mention. Why should my readings be questionable by anyone, and in anycase, apart from having a different opinion than Pammy, on amount of gears used down the strip, I belive the only dispute I've ever had, was wether my heads were flowed at 10" or 12". As it goes, my most recent research would lead me to belive my heads were flowed at 12", but when I did the math I found 10" was most likely, in my calculations. Trouble is, there are some damn knowledgeable folks here who's experiences with our motors is priceless, and the more I listen to them, the more I learn, and perhaps get things right next time.
Oh yeah, there was the "splined shaft" one as well, but I won that one, with Aarons help I'd like to add !
Anyway, I've got Denish's 5th edition now, so all you experts can eat shite and die.
Welcome to the frey Peaceman !
Rocket in England |
Greg Gower (Leveg)
| | Posted on Wednesday, November 15, 2000 - 05:47 am: |
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Rocket
sorry for the late reply to your question about flow calcs. The reason for my post was that someone commented that with what your heads flowed, you should be making x amount of power. My point was that cylinder head flow won't dictate how much power you will make from a given combo. If you have an engine making 100 H.P. fitted with a pair of heads that flow 120H.P. and you then make the ports flow 150 H.P. by making them a lot bigger, you will probably lose power - because you are trading gas velocity for flow you don't need i.e. the heads already flow more than the other components can support.
All that the flow calc will tell you is how much power you can potentially make before the head becomes the restriction, if you get the rest of it right.
Sorry Blake, I guess we should move all this to "More Power" huh?
Greg |
Sean Pepper (Rocketman)
| | Posted on Wednesday, November 15, 2000 - 02:41 pm: |
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Greg, sorry if this sounds conceited, but I am aware of ALL the parameters.
I responded to your post because of your claim that Denish's constants could be taken to new heights. I merely wanted to establish if the gap simply became larger betwix both ends of the scale, or if it became relative, meaning that what was once calculated at a theoretical constant of .30 would now become, about .33 (ie, 10%).
As I said previously, I'd presumed my heads were flowed at 10, and as they were flowed at the same time JH's Dragster heads were flowed, I was told they were identical. As the Dragster runs more cam and sucks through a 45, I drew a conclusion that my heads would still allow more power thanks to the very high flow, even though it doesn't appear to have subdued the performance of my motor, given that I run less cam and carb than the Dragster. It is still possible to have some more flow without loosing power.
The point you make is true, but it isn't neccessarily so !
Just because I haven't a dyno in my kitchen, doesn't mean I don't understand theory. In my Triumph days, I made the power, no problem, perhaps by using a very old book too ! TUNING FOR SPEED by Graham Walker, refered to as the "slide rule of motorcycling", and in 1947 right upto the 70's, this book was your dyno !
My 750 Morgo ran 13 dead in the early 80's. Never saw a dyno, but on the street, in top gear at 70mph, a GPZ 1100 couldn't get near it in a roll on to 100mph.
In an 1/8th mile, it was unbeatable by just about anything on the road.
Thrown together on a kitchen table !
Rocket in England |
Greg Gower (Leveg)
| | Posted on Thursday, November 16, 2000 - 08:06 am: |
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Rocket
Yes it's possible to have more flow without losing power - on an extremely well designed and developed head. On most production heads, I'm sorry but the Dyno would prove you wrong.
For the intake charge to continue flowing into the cylinder when the piston is moving up from BDC, and the intake valve is still well open, requires kinetic energy in the intake charge. That kinetic energy is a function of air velocity.
Cylinder filling increases as the square of air velocity.
Therefore, take a port that is too big and reduce it by 5%, lose 5% flow and you will still fill the cylinder with 5% more air. i.e. You will improve volumetric efficiency by 5%. You will also produce a more responsive engine with a much wider power band.
If you can produce peak air velocity of around 690 feet per second at maximum revs, you will produce the widest power band. The formula to estimate this is:
(Bore x Bore x Stroke x Max R.P.M.) / 190,000.
As far as the flow formula goes, I think most head shops still use the .43 @ 10" rule, then use a correction factor on top of that depending on the engine specs.
The Triumph is impressive. Like many British bikes, it probably had fairly small ports to start with.
Greg |
Sean Pepper (Rocketman)
| | Posted on Thursday, November 16, 2000 - 05:46 pm: |
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Greg, are you saying the TS head isn't an extremely well designed and developed head, especially one that's been worked on by Dick O'Brien ?
Shame on you man, for pointing out the inadequacy of the Evo heads, not to mention poor old Dick's best efforts !
I still have the Triumph. Like all old Brit bikes, it's in a million pieces, in a basket. One day, one day !
Rocket in England |
Greg Gower (Leveg)
| | Posted on Friday, November 17, 2000 - 03:06 am: |
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Sorry - the formula above is for minimum cross sectional area of the intake port, so the result is in square inches.
Greg |
Pamela O. Brown (Pammy)
| | Posted on Friday, November 17, 2000 - 01:01 pm: |
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This is a '99 X1 without PCIII and with PCIII
 |
Pamela O. Brown (Pammy)
| | Posted on Friday, November 17, 2000 - 01:06 pm: |
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well, that didn't come out like I hoped |
Jim Armstrong (Jima4media)
| | Posted on Friday, November 17, 2000 - 05:55 pm: |
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Pammy,
What didn't come out like you hoped, the picture, the dyno chart, or performance of the PC III on a '99 X-1, or the election in Florida? ;-)
Jim
X-2.5 |
Pamela O. Brown (Pammy)
| | Posted on Friday, November 17, 2000 - 08:03 pm: |
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The picture of the dyno chart...the bike picked up 6hp. The election in Fl is still too early to tell!
If you think the vote-counting is slow here...you ought to try driving in town!!!
Pammy |
Alan Levesque (Buellhandluke)
| | Posted on Saturday, November 25, 2000 - 07:33 pm: |
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2000 X1. It has a supercrapp / force intake / power commander III / hi-po O2 sensor / stock
ecu. it has the correct map from dynojet installed. Does anyone have any idea (ballpark)
how much hp it is making with these mods. The
bike is running better than it ever has but still
seems really slow. |
Pamela O. Brown (Pammy)
| | Posted on Saturday, November 25, 2000 - 10:23 pm: |
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Alan, The Dyno chart that I posted, above, has all the same mods as you except the force air intake system.
It did not run well at all with the map from dyno-jet.
It had to be modified a great deal. Of course we are here in Fla.
Pammy |
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